Converted to page and added heading

Summary:
Converted applet to use the new page component with PlasmoidHeadings for header and footer.

{F8247486}

Reviewers: #vdg, #plasma, ngraham

Reviewed By: #vdg, ngraham

Subscribers: ngraham, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D28996